The clinical and medical fields have longed for easy and simple technologies which measure insides of living bodies without giving any damage to them. An optical measurement is one of such technologies. The first reason for it is that the oxygen metabolism is related to specific chromatophores (hemoglobin, cytochrome a a3, myoglobin, etc.) or the concentration of light absorber and the concentration of the specific chromatophore can be obtained from the quantity of light absorption (between the visible ray and the near infrared ray). The second reason is that light rays can be easily handled by optical fibers. The third reason is that optical measurement is not harmful to living bodies when light rays are used correctly according to the Safety Standards (ANSIZ 136-1973 and JISC6802: 2 milliwatt per square millimeter).
An apparatus using such merits of the optical measurement and measuring the inside of a living body which applies light beams of visible wavelengths to near infrared wavelengths to a living body and collects the reflected light at a position 10 mm to 50 mm away from the illuminated position was disclosed for example by Japanese Non-examined Patent Publications No.63-277038 (1988) and No.H-5300887. Another apparatus which measures CT images of oxygen metabolism from light rays passing through a living body of 100 mm to 200 mm thick, or an optical CT apparatus was disclosed for example by Japanese Non-examined Patent Publications No.60-72542 (1985) and No.62-231625.
In application of the optical measurement which measures the characteristics due to living bodies to clinical fields, for example in measurement of a head, we can get the activation status of oxygen metabolism of a brain and local hemorrhage (breeding) in the brain. It is also possible to measure functions related to cerebral oxygen metabolism such as exercising, sensing, and further higher cerebral functions (e.g. thinking). In such measurements, images are much more powerful in analysis than data of measurement. For example, measurement and display using images are preferable for detection of positions which have a local oxygen metabolism change.
A multi-channel optical measuring apparatus is required to collect images. A multi-channel optical measuring system is disclosed by Japanese Non-examined Patent Publication H9-98972 (1997). However, it is substantially very important that we can check whether every channel of the system is normal before starting the multi-channel measurement.
An object of the present invention is to provide a multi-channel optical measuring apparatus which optically measures samples without causing any channel problem, processes information obtained by the measurement, and displays the selected items as images.